<!DOCTYPE HTML>

<html>
<head>
<title>OffscreenCanvas 2d flow on worker thread: Two Canvases</title>
<style type="text/css">
.nomargin {
  margin: 0px;
}
</style>
<script id="myWorker" type="text/worker">
/* This pixel test checks the following:
    1. Whether submission of frames for multiple canvases happen about the same
       time for OffscreenCanvas that are invoked in the same JS task.
    2. Whether overdraw frame in one animation loop is handled well.
    3. Whether the drawn 2d image is position upright.

    Correct end result of this test: The left canvas shows a seven-spike skyblue
    star on the top-left corner of a green background and the right canvas shows
    a sky-blue fill.
*/
var g_ctx1, g_ctx2;
var g_asyncCallbackNumber = 2;

self.onmessage = function(e) {
  g_ctx1 = e.data.offscreenCanvas1.getContext("2d");
  g_ctx2 = e.data.offscreenCanvas2.getContext("2d");

  startTest();
}

function startTest() {
  g_ctx1.fillStyle = "green";
  g_ctx1.fillRect(0, 0, 180, 200);

  requestAnimationFrame(() => {
    g_ctx2.fillRect(0, 0, 180, 200);
    if (--g_asyncCallbackNumber == 0) self.postMessage("");
  });

  function drawStar(ctx, cx, cy, spikes, outerRadius, innerRadius) {
    var rot = Math.PI / 2 * 3;
    var x = cx;
    var y = cy;
    var step = Math.PI / spikes;

    ctx.beginPath();
    ctx.moveTo(cx, cy - outerRadius);
    for (i = 0; i < spikes; i++) {
      x = cx + Math.cos(rot) * outerRadius;
      y = cy + Math.sin(rot) * outerRadius;
      ctx.lineTo(x, y);
      rot += step;

      x = cx + Math.cos(rot) * innerRadius;
      y = cy + Math.sin(rot) * innerRadius;
      ctx.lineTo(x, y);
      rot += step;
    }
    ctx.lineTo(cx, cy - outerRadius);
    ctx.closePath();
    ctx.lineWidth = 5;
    ctx.strokeStyle = 'black';
    ctx.stroke();
    ctx.fillStyle = 'skyblue';
    ctx.fill();
  }

  // Do something complex to g_ctx2.
  g_ctx2.fillStyle = "blue";
  g_ctx2.fillRect(0, 0, 180, 200);
  drawStar(g_ctx2, 90, 100, 25, 60, 40);
  // This g_ctx2 must be resolved at about the same time as the first
  // g_ctx1 above because they are in the same JS task, no matter how
  // complex the drawing operation is.
  requestAnimationFrame(() => {
    drawStar(g_ctx1, 70, 80, 7, 60, 30);

    if (--g_asyncCallbackNumber == 0) self.postMessage("");
  });

}

</script>
<script>
var g_swapsBeforeAck = 15;

function makeWorker(script)
{
   var blob = new Blob([script]);
   return new Worker(URL.createObjectURL(blob));
}

function waitForFinish()
{
  if (g_swapsBeforeAck == 0) {
    domAutomationController.send("SUCCESS");
  } else {
    g_swapsBeforeAck--;
    document.getElementById('container').style.zIndex = g_swapsBeforeAck + 1;
    requestAnimationFrame(waitForFinish);
  }
}

function main()
{
  var offscreenCanvas1 = document.getElementById("canvas1").transferControlToOffscreen();
  var offscreenCanvas2 = document.getElementById("canvas2").transferControlToOffscreen();

  var worker = makeWorker(document.getElementById("myWorker").textContent);
  worker.onmessage = function (e) {
      waitForFinish();
  };
  worker.postMessage(
      {offscreenCanvas1: offscreenCanvas1,
       offscreenCanvas2: offscreenCanvas2},
      [offscreenCanvas1, offscreenCanvas2]);
}
</script>
</head>
<body onload="main()">
<div style="position:relative; width:360px; height:200px; background-color:white">
</div>
<div id="container" style="position:absolute; top:0px; left:0px; font-size: 0">
<canvas id="canvas1" width="180" height="200" class="nomargin"></canvas>
<canvas id="canvas2" width="180" height="200" class="nomargin"></canvas>
</div>
</body>
</html>
